Shields or guards for rotating shafts have been common in the agricultural equipment field for some time. While most of such shields or guards have been provided for rotating shafts that do not alter or change their angular orientation relative to the vehicle during operation, guards have also been provided for power take-off (PTO) drive shafts and the driven shafts on the implements to which they couple, which shafts do angle relative to each other. Because the driven shaft on the implement must be coupled to and uncoupled from the PTO shaft each time the implement is connected to and disconnected from the tractor, such guards must be readily removable and either do not cover lubrication fittings or, if they do, make no special provision for lubrication because any necessary maintenance may be performed when the shafts are disconnected and the shields disabled or otherwise removed.
On certain articulated tractors, the engine is mounted on the front frame section and the main clutch is mounted on the rear frame section. Consequently, the drive line or shaft connecting the engine to the clutch must pass across the articulation joint and will be rotating whenever the engine is running, regardless of whether the tractor is in motion. Should this drive line break while the tractor is in operation, the operator's first inclination would be to arrest further movement of the vehicle by braking. However, until the engine is stopped, that portion of the broken drive line which remained connected to the engine would continue to rotate, and since flexible connections are necessary in this drive line to accommodate articulation, that portion will flail about damaging any components on the tractor within its reach.
Any guard for the drive shaft extending across the tractor's articulation point must accommodate the angular changes and still provide the shielding necessary to discourage contact between the shaft and any object that would be thrown by or would do damage to the shaft should contact occur while the shaft is rotating. In addition, the guard should permit lubrication of component parts of the drive shaft without removal or disablement thereof both with the tractor in any angle of articulation and with the drive shaft coming to rest in any orientation, i.e. any angle about its own axis of rotation.
Since a bellows, such as that disclosed in U.S. patent application Ser. No. 114,434, filed the same day as this application by George E. Bowman, David S. Faust and David T. Kataoka and entitled COVER FOR A TRACTOR'S ARTICULATION SPACE which may be provided as a cover for the area of articulation to improve the appearance of the tractor, is capable of being removed, a guard for a constant running drive line must protect an operator from inadvertant contact therewith, and must diminish the possibility of clothing becoming entangled therein when service or repair operations are performed with the bellows removed and the engine operating.
It is, therefore, an object of this invention to provide a guard for a constant-running shaft crossing the pivot or steering joint of an articulated tractor which discourages contact with the shaft, which accommodates the angular and distance changes due to articulation, which permits lubrication of component parts of said shaft without disturbing the guard, which minimizes damage from the shaft in the event it should break, which discourages both inadvertant contact with the shaft by an operator and which diminishes the possibility of clothing becoming entangled with the shaft.
It is also an object of this invention to provide such a guard for a drive shaft which permits lubrication of drive shaft components in any angle of articulation.
It is a further object of this invention to provide such a drive shaft guard which permits access for limited maintenance to the shaft's component parts regardless of the angular orientation of the shaft at rest.